Support reading ICC color profiles #81
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Signed-off-by: Benjamin Gilbert <[email protected]>
We have paintRegionARGB() which writes directly into an int array, and paintRegion() which scales and draws into a Graphics2D, but we could use an intermediate-level API that returns an image object directly from OpenSlide. Signed-off-by: Benjamin Gilbert <[email protected]>
BufferedImage uses an sRGB ColorModel by default. If a slide pyramid or
associated image has an ICC profile, attach a ColorModel containing that
profile to all BufferedImages produced from that image.
Callers of paintRegionARGB() don't receive a BufferedImage. For those
users, add OpenSlide.getColorModel() so the profile can be read
separately.
Graphics2D's documentation suggests that it handles color management, but
its drawImage() method apparently does not. If we therefore manually
invoke a ColorConvertOp in paintRegion(), the DICOM/Leica-4 test slide
throws an exception:
Exception in thread "AWT-EventQueue-0" java.awt.color.CMMException: LCMS error 13: Couldn't link the profiles
at java.desktop/sun.java2d.cmm.lcms.LCMS.createNativeTransform(Native Method)
at java.desktop/sun.java2d.cmm.lcms.LCMS.createTransform(LCMS.java:113)
at java.desktop/sun.java2d.cmm.lcms.LCMSTransform.doTransform(LCMSTransform.java:114)
at java.desktop/sun.java2d.cmm.lcms.LCMSTransform.colorConvert(LCMSTransform.java:149)
at java.desktop/java.awt.image.ColorConvertOp.ICCBIFilter(ColorConvertOp.java:350)
at java.desktop/java.awt.image.ColorConvertOp.filter(ColorConvertOp.java:277)
at org.openslide.OpenSlide.paintRegion(OpenSlide.java:326)
[...]
It seems that ColorConvertOp always uses perceptual rendering intent, not
the default intent encoded in the profile:
https://bugs.openjdk.org/browse/JDK-8216369
Not all profiles support perceptual rendering, which may be the cause of
the exception. If we're going to automatically perform color conversion,
we should do it predictably, not just when the Java CMS glue happens to do
the right thing. For now, don't try to do color conversion, either in
paintRegion() or any of the GUI code.
Closes: openslide#53
Signed-off-by: Benjamin Gilbert <[email protected]>
DCO signed off ✔️All commits have been signed off. You have certified to the terms of the Developer Certificate of Origin, version 1.1. In particular, you certify that this contribution has not been developed using information obtained under a non-disclosure agreement or other license terms that forbid you from contributing it under the GNU Lesser General Public License, version 2.1. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
BufferedImageuses an sRGBColorModelby default. If a slide pyramid or associated image has an ICC profile, attach aColorModelcontaining that profile to allBufferedImages produced from that image.Callers of
paintRegionARGB()don't receive aBufferedImage. For those users, addOpenSlide.getColorModel()so the profile can be read separately. To simplify reading slide regions with aColorModel, add anOpenSlide.readRegion()method that returns aBufferedImage.Graphics2D's documentation suggests that it handles color management, but itsdrawImage()method apparently does not. If we therefore manually invoke aColorConvertOpinpaintRegion(), theDICOM/Leica-4test slide throws an exception:It seems that
ColorConvertOpalways uses perceptual rendering intent, not the default intent encoded in the profile. Not all profiles support perceptual rendering, which may be the cause of the exception. If we're going to automatically perform color conversion, we should do it predictably, not just when the Java CMS glue happens to do the right thing. For now, don't try to do color conversion, either inpaintRegion()or any of the GUI code.Closes: #53